A phase 1 study of an off-the shelf, multi-neoantigen vector (ADXS-503) in subjects with metastatic non-small cell lung cancer (NSCLC) progressing on pembrolizumab as last therapy.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2616-2616
Author(s):  
Missak Haigentz ◽  
Suresh S. Ramalingam ◽  
Gregory James Gerstner ◽  
Balazs Halmos ◽  
Neil Morganstein ◽  
...  

2616 Background: ADXS-503 (A503) is an off-the-shelf, attenuated Listeria monocytogenes (Lm)-based immunotherapy bioengineered to elicit potent T cell responses against 22 tumor antigens commonly found in NSCLC (i.e., 11 hotspot mutations and 11 tumor-associated antigens, TAAs). Pembrolizumab (Pembro) is a programmed death receptor-1 (PD-1)- blocking antibody approved for the treatment of advanced lung cancer. A503 and Pembro have complementary mechanisms of immune activation and reversal of immune tolerance. Methods: A phase 1 study of A503 ± Pembro has been conducted in patients (pts) with metastatic squamous or non-squamous NSCLC. In dose-escalation part B, A503 was added-on to Pembro within 12 weeks of the first scan showing disease progression per RECIST criteria v1.1. Both, A503 (1 x108 CFU) and Pembro (200 mg) were infused by IV every 3 weeks until disease progression or limiting toxicity. The dose-escalation cohort has established safety, tolerability and immunogenicity of the combination therapy and it has been further expanded to evaluate efficacy (Goldman JW et.al., SITC 2020). Results: Nine pts have been treated and evaluated in Part B. Pembro + A503 combo has been well tolerated and without immune related AEs. Of the nine evaluable pts, one has achieved partial response (PR) and 3 stable disease (SD), yielding an overall response rate (ORR) of 11% and disease control rate (DCR) of 44%. Two patients have had clinical benefit for over 12 months (i.e., one PR and one SD) and both of them had been on Pembro therapy for 2 years before enrollment. The two other pts with SD have sustained it for almost 6 months thus far. Seven pts have been evaluated for immunogenicity. In all pts there was a transient release of pro-inflammatory cytokines and proliferation of cytotoxic- and memory-CD8+ T cells. Seven evaluable pts had antigen-specific T cells within 1-2 weeks after starting therapy and 4/7 showed antigen spreading. Conclusions: ADXS-503 as an add-on therapy to Pembro at disease progression has been well tolerated and it has induced antigen specific-T cell responses and durable disease control in 44% of pts. Part B cohort is currently enrolling additional pts to further explore the potential reversal of Pembro resistance with ADXS-503. Clinical trial information: NCT03847519.

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3496
Author(s):  
Seyer Safi ◽  
Yoshikane Yamauchi ◽  
Hans Hoffmann ◽  
Wilko Weichert ◽  
Philipp J. Jost ◽  
...  

Spontaneous T cell responses to tumor-associated antigens (TAs) in the peripheral blood of patients with non-small-cell lung cancer (NSCLC) may be relevant for postoperative survival. However, the conditions underlying these T cell responses remain unclear. We quantified the levels of 27 cytokines in the peripheral blood and tumor tissues from treatment-naïve patients with NSCLC (n = 36) and analyzed associations between local and systemic cytokine profiles and both TA-specific T cell responses and clinical parameters. We defined T cell responders as patients with circulating T cells that were reactive to TAs and T cell nonresponders as patients without detectable TA-specific T cells. TA-specific T cell responses were correlated with serum cytokine levels, particularly the levels of interleukin(IL)-4 and granulocyte colony-stimulating factor (G-CSF), but poorly correlated with the cytokine levels in tumor tissues. Nonresponders showed significantly higher serum IL-4 levels than responders (p = 0.03); the predicted probability of being a responder was higher for individuals with low serum IL-4 levels. In multivariable Cox regression analyses, in addition to IL-4 (hazard ratio (HR) 2.8 (95% confidence interval (CI): 0.78–9.9); p = 0.116), the age-adjusted IL-8 level (HR 3.9 (95% CI: 1.05–14.5); p = 0.042) predicted tumor recurrence. However, this study included data for many cytokines without adjustment for multiple testing; thus, the observed differences in IL-4 or IL-8 levels might be incidental findings. Therefore, additional studies are necessary to confirm these results.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 244-244
Author(s):  
Javier Munoz ◽  
Samantha Jaglowski ◽  
Matthew S. McKinney ◽  
Iris Isufi ◽  
Patrick J. Stiff ◽  
...  

Background: The Antibody-Coupled T-cell Receptor (ACTR) platform is an autologous engineered T-cell therapy that combines the cell-killing ability of T cells and the tumor-targeting ability of co-administered antibodies to exert potent antitumor immune responses. ACTR087 comprises the extracellular domain of CD16 linked to a CD3ζ-signaling domain and a 4-1BB co-stimulatory domain. Here we present the clinical experience from Study ATTCK-20-2 (NCT02776813), a multicenter, phase 1 study of ACTR087 in combination with rituximab in subjects with relapsed or refractory (R/R) CD20+ NHL. Methods: The main objectives of this first-in-human study were to evaluate the safety and antitumor activity of ACTR087+rituximab. Other objectives included evaluating ACTR T-cell persistence and other correlative biomarkers. Subjects must have had CD20+ NHL that was R/R after prior treatments, which must have included anti-CD20 antibody-containing chemotherapy. Subjects received lymphodepleting chemotherapy (cyclophosphamide and fludarabine) for 3 days, followed by rituximab and a single dose of ACTR087. Additional doses of rituximab were administered q3w until disease progression, unacceptable toxicity, or Investigator decision. The study included a dose escalation phase (increasing doses of ACTR087) and an expansion phase (ACTR087 at the preliminary recommended phase 2 dose [RP2D]); all subjects received rituximab at a fixed dose of 375 mg/m2 q3w. Results: Two dose levels (DL) of ACTR087 were evaluated during dose escalation (n=17). The MTD was exceeded at DL2, with severe cases of cytokine release syndrome (CRS) and neurotoxicity. Statistical analysis of the relationship between non-hematologic toxicity and ACTR+ T-cell doses was retrospectively performed (two-parameter Bayesian logistic regression model) to estimate an RP2D of 35×106 ACTR+ T cells. Nine subjects enrolled in an expansion cohort and received ACTR087 at this RP2D in combination with rituximab. Among all subjects treated (n=26), the majority (69%) were diagnosed with DLBCL. Subjects had received a median of 3 (range 1-9) prior lines of therapy, with 77% having received ≥3 prior lines. ACTR087 showed dose-dependent expansion with peak levels generally observed 7 to 14 days post administration. In subjects with ongoing clinical response (CR), ACTR remained detectable through the last timepoint evaluated. Across all cohorts, Grade ≥3 TEAEs reported in >3 subjects regardless of causality were limited to hematologic events. Potential T cell-mediated toxicities were observed, including 4 serious cases of CRS (Gr 4 in 2 subjects, both with fatal sepsis) and 2 serious cases of neurotoxicity (1 Gr 5, 1 Gr 4 in a subject with fatal septic shock). Elevated baseline inflammatory markers (eg, ferritin, CRP) were observed in patients who developed Gr ≥3 CRS and neurotoxicity post ACTR087. Of note, severe CRS presented without fever and events occurred >7 days post ACTR087. Clinical activity was reported with an ORR of 50% in all dose levels tested, including durable complete responses, with one subject in CR for 869+ days (Table 1). Conclusions: ACTR087+rituximab demonstrated antitumor activity, with observed safety events that are expected with other autologous T-cell products. The time to onset and clinical presentation of severe CRS and neurotoxicity events in this study informed the safety monitoring and adverse reaction management guidance across clinical studies of ACTR T-cell products. Data from this first-in-human study of ACTR087+rituximab confirm the proof of concept and will be used to guide further development for the ACTR platform. Updated clinical data, as well as expanded biomarker correlations to efficacy and safety, will be presented. Disclosures Munoz: Pharmacyclics /Janssen: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy; Fosunkite: Speakers Bureau; AstraZeneca: Speakers Bureau; Kyowa: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy, Research Funding, Speakers Bureau; Kite/Gilead: Consultancy, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Alexion: Consultancy; Portola: Research Funding; Incyte: Research Funding; Bayer: Consultancy, Speakers Bureau; Merck: Consultancy. Jaglowski:Kite: Consultancy, Other: advisory board, Research Funding; Novartis: Consultancy, Other: advisory board, Research Funding; Unum Therapeutics Inc.: Research Funding; Juno: Consultancy, Other: advisory board. Isufi:Celgene: Consultancy; Novartis: Consultancy; Astra Zeneca: Consultancy. Stiff:Gamida-Cell: Research Funding; Incyte: Research Funding; Cellectar: Research Funding; Unum: Research Funding; Gilead/Kite Pharma: Consultancy, Honoraria, Research Funding; Amgen: Research Funding. Sachs:Unum Therapeutics Inc.: Employment. Ranger:Unum Therapeutics Inc.: Employment. Harris:Unum Therapeutics Inc.: Employment. Payumo:Unum Therapeutics Inc.: Employment. Akard:Bristol-Myers Squibb: Speakers Bureau; Gilead: Speakers Bureau; Takeda: Speakers Bureau; Novartis: Speakers Bureau; Celgene: Speakers Bureau.


2012 ◽  
Vol 209 (4) ◽  
pp. 641-651 ◽  
Author(s):  
Afam A. Okoye ◽  
Mukta Rohankhedkar ◽  
Chike Abana ◽  
Audrie Pattenn ◽  
Matthew Reyes ◽  
...  

The development of AIDS in chronic HIV/simian immunodeficiency virus (SIV) infection has been closely linked to progressive failure of CD4+ memory T cell (TM) homeostasis. CD4+ naive T cells (TN) also decline in these infections, but their contribution to disease progression is less clear. We assessed the role of CD4+ TN in SIV pathogenesis using rhesus macaques (RMs) selectively and permanently depleted of CD4+ TN before SIV infection. CD4+ TN-depleted and CD4+ TN-repleted RMs were created by subjecting juvenile RMs to thymectomy versus sham surgery, respectively, followed by total CD4+ T cell depletion and recovery from this depletion. Although thymectomized and sham-treated RMs manifested comparable CD4+ TM recovery, only sham-treated RMs reconstituted CD4+ TN. CD4+ TN-depleted RMs responded to SIVmac239 infection with markedly attenuated SIV-specific CD4+ T cell responses, delayed SIVenv-specific Ab responses, and reduced SIV-specific CD8+ T cell responses. However, CD4+ TN-depleted and -repleted groups showed similar levels of SIV replication. Moreover, CD4+ TN deficiency had no significant effect on CD4+ TM homeostasis (either on or off anti-retroviral therapy) or disease progression. These data demonstrate that the CD4+ TN compartment is dispensable for CD4+ TM homeostasis in progressive SIV infection, and they confirm that CD4+ TM comprise a homeostatically independent compartment that is intrinsically capable of self-renewal.


2007 ◽  
Vol 204 (11) ◽  
pp. 2679-2692 ◽  
Author(s):  
Dennis J. Hartigan-O'Connor ◽  
Kristina Abel ◽  
Joseph M. McCune

The impact of regulatory T cells (T reg cells) on the course of HIV and SIV disease is unknown. T reg cells could suppress protective antiviral responses and accelerate disease progression. Alternatively, these cells might block T cell activation and thereby limit viral replication as well as activation-associated immunopathology. Given the higher frequency of T reg cells known to be present during human fetal ontogeny, such influences may be most important in the context of perinatal infection. We found that infant macaques had higher fractions of CD4+CD25+CD127lowFoxP3+ T reg cells in the peripheral blood and in lymphoid tissues, and that these T reg cells showed greater in vitro suppressive activity on a per cell basis. Infant and adult macaques were infected with SIVmac251 to test the influence of the T reg cell compartment on SIV-specific immune responses. After infection with SIV, most (three out of four) infant macaques had persistently high viral loads, weak and transient SIV-specific CD4+ and CD8+ T cell responses, and rapid disease progression. T reg cells in the infant but not in the adult directly suppressed SIV-specific CD4+ T cell responses, which were detectable only after depletion of T reg cells. In the case of both the infant and the adult macaque, T reg cells were not able to directly suppress SIV-specific CD8+ T cell responses and had no apparent effect on T cell activation. In aggregate, these observations suggest that the T reg cell compartment of the infant macaque facilitates rapid disease progression, at least in part by incapacitating SIV-specific CD4+ T cell responses.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A326-A326
Author(s):  
Brendan Horton ◽  
Duncan Morgan ◽  
Elen Torres-Mejia ◽  
Maria Zagorulya ◽  
Vidit Bhandarkar ◽  
...  

BackgroundIn non-small cell lung cancer (NSCLC), response to checkpoint blockade therapy (CBT) is associated with tumor-infiltrating CD8+ T cells, but not all T cell-infiltrated tumors respond to CBT. The subgroup of T cell-infiltrated but CBT-resistant tumors has been clinically described as containing ”non-functional” T cell responses. Mechanisms governing the generation of non-functional T cell responses remain poorly understood, and treatment options for this subgroup are limited.MethodsWe utilized a transplantable, syngeneic murine NSCLC cell line derived from an autochthonous NSCLC driven by KrasG12D expression and p53 deletion (KP cell line) to model non-functional T cell responses. To study antigen-specific responses, we engineered KP cells to express the model CD8+ T cell antigen SIY for certain experiments. CBT consisted of combined anti-CTLA-4 and anti-PD-L1 therapy.ResultsOrthotopic KP lung tumors failed to respond to CBT, but KP flank tumors were controlled by CBT. Lung and flank tumors contained activated CD8+ T cells, providing a platform to compare functional and non-functional CD8+ T cell responses in NSCLC. Single-cell RNA sequencing revealed that lung tumor-infiltrating CD8+ T cells lacked effector and exhaustion molecules despite clonal expansion. Analysis of antigen-specific CD8+ T cells revealed that this lung cancer-specific T cell dysfunction was established during priming in lung-draining mediastinal lymph nodes (mLN) despite robust T cell proliferation. RNA sequencing and flow cytometry of antigen-specific CD8+ T cells found that T cells primed in the mLN underwent blunted effector differentiation characterized by a lack of effector molecules CD25, Granzyme B, and TIM-3, but retention of TCF-1. This phenotype persisted in lung tumors, consistent with our initial observations of absent effector and exhaustion molecule expression. Many CD8+ T cells from NSCLC patients expressed an analogous gene expression program distinct from T cell exhaustion. TCF-1+ CD8+ T cells in lung tumors did not mediate tumor control and failed to differentiate into effector cells after CBT. To investigate alternative therapeutic strategies of reinvigorating lung tumor-reactive T cells, we focused on IL-2 and IL-12, as expression of their receptors was reduced in mLN-primed T cells. Administering recombinant IL-2 and IL-12 was sufficient to restore effector T cell differentiation, induce lung tumor control, and significantly extend survival of lung tumor-bearing mice.ConclusionsOur results suggest that non-functional CD8+ T cell responses in NSCLC arise from failed effector T cell differentiation during priming. Transient combination therapy with IL-2 and IL-12 overcomes this dysfunctional state to induce protective T cell responses in CBT-resistant tumors.Ethics ApprovalAll mouse experiments were approved by MIT’s Committee on Animal Care (CAC) - DHHS Animal Welfare Assurance # D16-00078


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1587-1587
Author(s):  
Ian W. Flinn ◽  
Jason R. Westin ◽  
Jonathon B. Cohen ◽  
Luke P. Akard ◽  
Samantha Jaglowski ◽  
...  

Background: The Antibody-Coupled T-cell Receptor (ACTR) platform is an autologous engineered T-cell therapy that combines the cell-killing ability of T cells and the tumor-targeting ability of co-administered antibodies to exert potent antitumor immune responses. ACTR707 comprises the extracellular domain of CD16 linked to a CD3ζ signaling domain and a CD28 co-stimulatory domain. ACTR707 is in clinical development in combination with rituximab (NCT03189836) or trastuzumab (NCT03680560). Here we present clinical findings from the dose escalation phase of Study ATTCK-20-03, an ongoing, multicenter, phase 1 study of ACTR707+rituximab in subjects with relapsed or refractory (R/R) CD20+ NHL. Methods: The primary objectives of this first-in-human study are to evaluate the safety of the combination of ACTR707 and rituximab and to determine a recommended phase 2 dose (RP2D). Other objectives include evaluating antitumor activity and ACTR T-cell persistence. Subjects must have CD20+ NHL that is R/R after prior treatments, which must include anti-CD20 antibody-containing chemotherapy. Subjects receive lymphodepleting chemotherapy (cyclophosphamide and fludarabine) for 3 days, followed by rituximab and a single dose of ACTR707. Additional doses of rituximab are administered q3w until disease progression, unacceptable toxicity, or Investigator decision. The study includes a dose escalation phase (increasing doses of ACTR707 with fixed dose of rituximab at 375 mg/m2 q3w) and an expansion phase at the RP2D. Results: Six subjects received ACTR707 at Dose Level 1 (DL1; 23-38×106 ACTR+ T cells), 3 subjects at DL2 (30-50×106 ACTR+ T cells), and 5 subjects at DL3 (45-55×106 ACTR+ T cells). The majority of the subjects were diagnosed with DLBCL (93%) and had refractory disease (71%), defined as progressive disease as the best response to any prior treatment or relapse <1 year post autologous stem cell transplant. In DL1 through DL3, as of 27 May 2019, there were no dose-limiting toxicities, AEs of cytokine release syndrome (CRS), serious or severe neurologic AEs, or AEs leading to deaths on treatment. TEAEs reported in >2 subjects, regardless of causality or grade, included neutropenia, thrombocytopenia, anemia, febrile neutropenia, pyrexia, cough, constipation, diarrhea, nausea, and vomiting. SAEs considered possibly related to ACTR707 were febrile neutropenia (n=2) and cytopenia (n=1). ACTR707 expansion generally reached peak levels within 1 to 2 weeks after administration. All subjects with complete response (CR) up to 1 year had detectable ACTR at the last timepoint evaluated. Higher ACTR707 CD8:CD4 T-cell ratios were associated with clinical responses. Clinical activity was reported across DL1 through DL3, with an overall response rate of 64% including durable complete responses (CRs), with one subject in CR for 387+ days (Table 1). Conclusions: Data available from DL1 through DL3 of ACTR707+rituximab suggest that clinical responses can be achieved without severe T cell-mediated toxicities (eg, CRS and neurotoxicity) that have been reported with other autologous T-cell products. Dose escalation continues at a target dose of 80×106 ACTR+ T cells; enrollment in DL4 (n=6) was recently completed. Updated data, including identified correlates of clinical outcomes, will be presented for DL1 through DL4. Disclosures Flinn: TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; AbbVie, Seattle Genetics, TG Therapeutics, Verastem: Consultancy; TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; Acerta Pharma, Agios, Calithera Biosciences, Celgene, Constellation Pharmaceuticals, Genentech, Gilead Sciences, Incyte, Infinity Pharmaceuticals, Janssen, Karyopharm Therapeutics, Kite Pharma, Novartis, Pharmacyclics, Portola Pharmaceuticals: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding. Westin:Genentech: Other: Advisory Board, Research Funding; Janssen: Other: Advisory Board, Research Funding; Kite: Other: Advisory Board, Research Funding; Unum: Research Funding; Curis: Other: Advisory Board, Research Funding; Juno: Other: Advisory Board; MorphoSys: Other: Advisory Board; 47 Inc: Research Funding; Celgene: Other: Advisory Board, Research Funding; Novartis: Other: Advisory Board, Research Funding. Cohen:Genentech, Inc.: Consultancy, Research Funding; Takeda Pharmaceuticals North America, Inc.: Research Funding; Gilead/Kite: Consultancy; LAM Therapeutics: Research Funding; UNUM: Research Funding; Hutchison: Research Funding; Astra Zeneca: Research Funding; Lymphoma Research Foundation: Research Funding; ASH: Research Funding; Bristol-Meyers Squibb Company: Research Funding; Seattle Genetics, Inc.: Consultancy, Research Funding; Janssen Pharmaceuticals: Consultancy. Akard:Celgene: Speakers Bureau; Novartis: Speakers Bureau; Takeda: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Gilead: Speakers Bureau. Jaglowski:Juno: Consultancy, Other: advisory board; Kite: Consultancy, Other: advisory board, Research Funding; Unum Therapeutics Inc.: Research Funding; Novartis: Consultancy, Other: advisory board, Research Funding. Sachs:Unum Therapeutics Inc.: Employment. Ranger:Unum Therapeutics Inc.: Employment. Harris:Unum Therapeutics Inc.: Employment. Payumo:Unum Therapeutics Inc.: Employment. Bachanova:Celgene: Research Funding; Gamida Cell: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; GT Biopharma: Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Novartis: Research Funding.


2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 206-206 ◽  
Author(s):  
Vincent M. Chung ◽  
Ferdynand Kos ◽  
Nicola Hardwick ◽  
Yuan Yuan ◽  
Joseph Chao ◽  
...  

206 Background: Mutations in the p53 gene are present in a majority of solid tumors, resulting in the accumulation of oncogenic and potentially immunogenic p53 protein within tumor cells. We have developed a genetically engineered Modified Vaccinia Ankara (MVA) virus to express wild type p53 transgene (p53MVA) as an immunotherapeutic strategy. We observed robust p53-specific CD8+ T cell responses which were further enhanced by anti-PD-1 treatment. This phase 1 study evaluates the safety and tolerability of the p53MVA vaccine in combination with pembrolizumab. Methods: Patients with non-small cell lung, head and neck squamous cell (HNSCC), hepatocellular (HCC), renal cell, melanoma, bladder, soft tissue sarcoma, triple-negative breast (TNBC), pancreatic (PDAC) and MSI high colorectal cancer failing or intolerant to standard treatment were eligible. Confirmation of p53 involvement by immunohistochemistry or mutational analysis was required for eligibility. A 3-at-risk rolling design was employed and patients received 5.6 x 108 pfu p53MVA for 3 doses in combination with 200 mg pembrolizumab for 7 doses every 3 weeks. Blood draws for immunological monitoring were obtained pre-treatment and up to week 19. Results: Two patients (TNBC and HNSCC) showed clinical benefit associated with durable p53-specific CD8+ T cell responses with gene expression pathway scores of T cell function and associated immune response categories elevated for more than 6 months. The TNBC patient had complete regression of cutaneous metastases and stable disease for > 6 months. Two patients (TNBC and PDAC) were on study for 35 and 9 weeks respectively; however, p53-specific T cells were not generated. Four patients (HCC, PDAC and 2 with TNBC) had rapidly progressive disease. Conclusions: Targeting p53 antigen associated with cancer using a viral vaccine p53MVA in combination with PD-1 blockade represents a novel immunotherapeutic approach capable of stimulating systemic immune responses and associated clinical benefit. Clinical trial information: NCT02432963.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A415-A415
Author(s):  
Maura Gillison ◽  
Roger Cohen ◽  
Przemyslaw Twardowski ◽  
Ammar Sukari ◽  
Melissa Johnson ◽  
...  

BackgroundGEN-009 is an adjuvanted personalized cancer vaccine containing up to 20 neoantigens selected by ATLAS™, an ex vivo bioassay screening autologous T cells to identify both neoantigens as well as Inhibigens™ empirically and without in silico predictions. Inhibigen-specific T cells suppress immunity and have been shown to accelerate tumor progression in mice. Inhibigens are avoided in GEN-009. Previous data from patients treated with GEN-009 monotherapy showed 99% of selected peptides generated immune responses including ex vivo CD4+ and CD8+ fluorospot responses specific for 51% and 41% of immunized peptides respectively.MethodsGEN-009 is being evaluated in patients (pts) with advanced cancer who received standard-of-care (SOC) PD-1 inhibitor as monotherapy or in combination therapy during vaccine manufacturing; they subsequently received 5 vaccine doses over 24 weeks in combination with the PD-1 inhibitor. Patients who progressed prior to vaccination could receive alternate therapy followed by GEN-009 combined with an appropriate salvage regimen. Peripheral T cell responses were evaluated pre-and post-vaccination by dual-analyte fluorospot assays measured both directly ex vivo and after in vitro stimulation.ResultsAs of August 18, 2020, 15 pts received GEN-009 in combination with a PD-1 inhibitor. Their median TMB was 1.37Mut/mb (range 0.31–6.55), with a median of 24 (6–99) neoantigens and 16 (1–86) Inhibigens. The number of neoantigens in each manufactured vaccine ranged from 4–18 (median 13). GEN-009-related adverse events were limited to Grade 1 injection site reactions. Ex vivo T cell responses peaked after the third vaccination for IFNγ and some patients showed evidence of epitope spread. The initial 5 patients are evaluable for antitumor activity with at least 3 months follow up after first vaccination. Three patients experienced early tumor responses followed by stabilization on PD-1 inhibitor SOC and demonstrated a further reduction in tumor volume after GEN-009 vaccination (figure 1). One patient experienced a complete response prior to vaccination and the 5th patient had progression on SOC, but had a Partial Response to salvage and remains stable after vaccination.Abstract 390 Figure 1Individual patient spider plots. Percent change in target lesion diameter over timeConclusionsVaccination with GEN-009 in combination with PD-1 CPI is feasible for patients with advanced solid tumors with little additive toxicity. Preliminary data demonstrate induction of robust, neoantigen-specific immune responses and a potential expansion of stimulatory targets with epitope spreading in the presence of PD-1 inhibitor. Possible additive antitumor activity in combination with PD-1 inhibitors is suggested by tumor shrinkage following GEN-009 dosing. More mature response and immunogenicity data on 10 additional patients is anticipated for November.Trial RegistrationClinicalTrials. gov NCT03633110Ethics ApprovalThe study was approved by Western Institutional Review Board, approval number 1-1078861-1.


2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S397-S397
Author(s):  
Susan Johnson ◽  
Clarissa Martinez ◽  
Mario Cortese ◽  
Josefina Martinez ◽  
Shaily Garg ◽  
...  

Abstract Background Covid-19 has accelerated global demand for easily distributed vaccines. Furthermore, as variant SARS-CoV-2 strains that circumvent antibody responses emerge, cross-protective vaccines provide substantial public health benefits. Vaxart is developing a shelf stable oral tablet vaccine that incorporates both the spike (S) and the more conserved nucleocapsid (N) proteins. Vaxart’s vaccine platform uses a non-replicating adenovirus and a TLR3 agonist as an adjuvant. Methods In an open-label phase 1 clinical study, 35 healthy subjects received either a single low (1x1010 IU; n=15) or high (5x1010 IU; n=15) dose of the vaccine candidate VXA-CoV2-1 with a small cohort receiving 2 low doses. PBMCs were taken at pre- and 7 days post-vaccination and restimulated with S and N peptides from SARS-CoV-2 or the 4 human endemic coronaviruses (HCoV). Cells were stained for CD4/CD8/CD107a (surface) and IFNγ/TNFα (intracellular). Subjects that received an intramuscular (i.m.) mRNA vaccine had PBMCs taken at the same timepoints and were compared in the same assay. Results The study’s results indicate that the VXA-CoV2-1 tablet was well tolerated. The majority of subjects had an increase in S-specific anti-viral CD8+ T cell responses. 19/26 (73%) subjects had a measurable CD8+ T cell response on day 8 above baseline, on average 1.5-4.6%. In a comparator experiment with the 2 SARS-CoV-2 i.m. mRNA vaccines, VXA-CoV2-1 outperformed other vaccine candidates with a >3.5-fold increase in S specific antiviral CD8 T cell responses. T cell responses specific to the 4 endemic HCoV were increased by 0.6% in subjects given VXA-CoV2-1. Conclusion Here we describe a room temperature stable tablet that induces SARS-CoV-2 S specific CD8 T cells of high magnitude after one dose in humans. Overall, the level of antiviral SARS-CoV-2 specific T cells, particularly IFNg-producing CD8s, induced following oral immunization with VXA-CoV2-1 are of higher magnitude than the mRNA vaccines currently in use against COVID-19. T cell responses against 4 endemic HCoV were also induced. Because T cells may be important in protecting against death and severe infection, these results suggest that VXA-CoV2-1 could be cross-protective against a wide array of emerging pandemic coronaviruses. Disclosures Susan Johnson, PhD, Vaxart (Employee) Clarissa Martinez, MPH, Vaxart (Employee) Mario Cortese, PhD, Vaxart (Employee) Josefina Martinez, n/a, Vaxart (Employee) Shaily Garg, BS, Vaxart (Employee) Nadine Peinovich, MPH, Vaxart (Employee) Emery Dora, n/a, Vaxart (Employee) Sean Tucker, PhD, Vaxart (Employee)


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A385-A385
Author(s):  
Jonathan Goldman ◽  
Thomas Stinchcombe ◽  
Gregory Gerstner ◽  
Missak Haigentz ◽  
Surya Vangala ◽  
...  

BackgroundADXS-503 (A503) is an off-the-shelf, attenuated Listeria monocytogenes (Lm)-based immunotherapy bioengineered to elicit potent T cell responses against 22 tumor antigens commonly found in NSCLC (i.e., 11 hotspot mutations and 11 tumor-associated antigens, TAAs). Pembrolizumab (Pembro) is a programed death receptor-1 (PD-1)- blocking antibody approved for the treatment of advanced lung cancer. A503 and Pembro have complementary mechanisms of immune activation and reversal of immune tolerance.MethodsWe conducted a phase 1 study of A503 ± Pembro in patients (pts) with metastatic squamous or non-squamous NSCLC. In Part A, A503 alone has been tested at two dose levels (i.e., 1 × 108 and 5 × 108 CFU) in pts refractory or intolerant to prior systemic therapy. In dose escalation Part B, A503 has been evaluated at the lower dose level (DL) in combination with Pembro within 6 weeks of presenting with disease progression per RECIST criteria v1.1. Part C dose expansion cohort with A503 + Pembro has started for first-line treatment in the metastatic setting. A503 ± Pembro (200 mg) are infused by IV every 3 weeks until disease progression or limiting toxicity. Main endpoints include safety, tolerability and immune-correlative data.ResultsTwelve patients have been treated: 7 in Part A, 4 in Part B-DL1 and 1 in Part C. No pts in Part A experienced dose-limiting toxicities at the 2 DLs tested. A503+ Pembro has also been well tolerated in 4 pts treated in Part B-DL1 and in one in Part C. No immune related AEs have been reported in Part B or Part C. Three evaluable pts in Part A achieved stable disease (SD). Of the three evaluable pts in Part B-DL1 one has achieved SD for 8 months and the second one a partial response for over 6 months; both of these patients had been on Pembro therapy for 2 years before enrollment. The 3rd pt showed progressive disease. ADXS-503 induced transient release of pro-inflammatory cytokines, activation of cytotoxic- and memory-CD8+ T cells against antigens in the construct and antigen spreading in peripheral blood across all cohorts. Preliminary data in on-therapy biopsies showed increased PD-L1 expression and decreased Treg cell counts. Part B -DL1 cohort has thus been expanded to further explore the potential reversal of Pembro resistance with ADXS-503 in these pts.ConclusionsADXS-503 alone and in combination with Pembro has demonstrated a manageable safety profile and induction of antigen specific T cell responses. The potential effect of A503 to reverse resistance to Pembro is now being studied in an expansion cohort and this combination approach is also being evaluated in the first line treatment setting (Part C).Ethics ApprovalThis study was approved by all Institution’s Ethics Board participating in the trial.AcknowledgementsDr.S Miglani and Dr.M Chopra (AWINSA group) for PV review, Precision for Medicine for immune-correlative work and Abhay Sheeri for data analyses.Trial RegistrationNCT03847519


Sign in / Sign up

Export Citation Format

Share Document